This research project is designed to evaluate the effectiveness of testosterone enanthate for the induction and maintenance of azoospermia in normal and adult males. The study period will be subdivided into three units: control or predrug - three months; drug administration - ten months; and recovery - six months. Throughout the study, seminal fluid specimens will be obtained from each man for measurements of hFSH, hLH, testosterone, and toxicology. The effect of testosterone enemthate on lipoproteins by determining cholesterol, triglyceride, and betalipoproteins will be examined closely in all men throughout the study